Muhammad bin Ishaq narrated that Muhammad bin Ja`far bin Az-Zubayr said that `Urwah bin Az-Zubayr explained this Ayah,يأَيُّهَا الَّذِينَ ءَامَنُواْ اسْتَجِيبُواْ لِلَّهِ وَلِلرَّسُولِ إِذَا دَعَاكُمْ لِمَا يُحْيِيكُمْ(O you who believe! Answer Allah and (His) Messenger when he calls you to that which will give you life,) "Answer when called to war (Jihad) with which Allah gives you might after meekness, and strength after weakness, and shields you from the enemy who oppressed you.